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New to imaging during lockdown EQ advice please.

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Hi Ive just got into Astrophotography before lockdown. Im getting to grips with my HQ5 goto and my Canon 1100d. Also used a webacam which seems to have broken, just ' whiteing' out so im looking to the future and thnking about buying a guide cam (for when I get into guiding) that can replace the webcam for planetary and lunar/solar. My scope is 630mm f4.9 130mm reflector, which is widefield. My question is . Will the guide cam give similar views to the webacm (i.e highly Magnified) AND should I get a colour OR mono guidecam? Would it be any use for deepsky ( the smaller stuff) as opposed to the DSLR? My understanding is that a 1.2mp guide cam sensor would resolve similar to cropping my 12mp DSLR so i wouldnt gain any advantage. Webcam Image field of view. 

moon 1st attempt.jpg

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You can use programs like this one: https://astronomy.tools/calculators/field_of_view/ to get an idea of what FOV a certain camera/scope combination will give you for all types of objects. Guidecams will give small a FOV as they tend to have small sensors, for DSO's such as galaxies or large nebula, you need either a smaller focal length scope or a larger sensor (or both)

If you are using the guidecam in a guiding role, the FOV of the guidecam isn't too important purely in terms of matching your main camera. What is important is image scale. This will help make sure that your guiding is accurate and the focal length of the guidescope is sufficient.

This can be calculated by: (imager focal length) / (guider focal length) * (guider pixel size) / (imager pixel size). Most people will advise that this number should be 3 or less for the best guiding performance although this is rough.

You also will want to use a monochrome guide cam as these are more sensitive to light and colour doesnt matter for guiding anyway. Its up to you though if you plan to use it for real imaging as well then colour may be worth thinking about.

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Keep away from counting pixels when comparing chips and don't think of 'magnification.' Stick to these key numbers:

In given optics...

Pixel size. Smaller pixels increase the resolution of small details and make a larger screen image of an object. This is going to 'get you closer.'

Chip size determines what will fit in your field of view. Having a small chip which holds only a part of your object or makes it fill the frame does not 'get you closer.' It just crops your field.



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  • 2 months later...


If the planets are badly placed right now should I just use my webcam and get practice with them and wait to buy a planetary camera? 

Anyone know which is best camera for planetary, detailed lunar, possibly trying for sunspots. Zwo asi 224 290 or 385? 

My current scopes are 130mm f5 Newtonian, 150 f8 Newtonian. 2 and 3 x barlows.... I have a canon 1100d I want to use  for wide field and possibly eaa. Should I get practice with this before looking for an eaa camera? 

Am I answering my own questions lol 

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